Pexidartinib

Pexidartinib is used in adults to treat giant cell tumor of the tendon sheath (also known as tenosynovial giant cell tumor or pigmented villonodular synovitis) that is not expected to get better with surgery.

Pexidartinib is available only through a special program. You must be registered in the program and understand the risks and benefits of pexidartinib.

Pexidartinib may also be used for reasons not mentioned in this medication guide.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Pexidartinib is usually taken twice per day with a low-fat meal (about 11 to 14 grams of fat).

Swallow the capsule whole and do not crush, chew, break, or open it.

If you vomit shortly after taking pexidartinib, do not take another dose. Take your next dose as scheduled.

You will need frequent blood tests to check your liver function before and during treatment with pexidartinib. Your next dose may be reduced, delayed, or permanently discontinued based on the results.

Your doctor will need to check your progress on a regular basis.

You may need to follow a special diet. Follow all instructions from your doctor or dietitian. Learn about the foods you should eat or avoid.

Keep the medicine in the original container, along with the canister of moisture-absorbing preservative. Store tightly closed at room temperature, away from moisture and heat.

Pexidartinib can damage your liver. You will need regular blood tests to monitor your liver function before and throughout your treatment with pexidartinib.

Stop taking pexidartinib and contact your doctor immediately if you notice dark urine or jaundice (yellowing of the skin or eyes).

Inform your doctor if you experience other signs of liver issues, such as loss of appetite, pain in the upper right side of your stomach, nausea, vomiting, tiredness, itching, or fever.

Tell your doctor if you have or have ever had:

• liver or kidney disease.

Pexidartinib can harm an unborn baby if the mother or the father is using this medicine.

• If you are a woman, you may need a pregnancy test to make sure you are not pregnant. Use birth control while using this medicine and for at least 1 month after your last dose.
• If you are a man, use birth control if your sex partner is able to get pregnant. Keep using birth control for at least 1 week after your last dose.
• Tell your doctor right away if a pregnancy occurs.

Pexidartinib can make birth control pills less effective. Ask your doctor about other birth control options such as an injection, implant, skin patch, vaginal ring, condom, diaphragm, cervical cap, or contraceptive sponge.

Pexidartinib may affect fertility in men or women. Pregnancy could be harder to achieve while either parent is using this medicine.

Do not breastfeed while using this medicine, and for at least 1 week after your last dose.

Get emergency medical help if you notice signs of an allergic reaction: hives, difficulty breathing, swelling of your face, lips, tongue, or throat.

Stop using pexidartinib and call your doctor right away if you have dark urine or jaundice (yellowing of the skin or eyes).

Pexidartinib may cause serious side effects. Call your doctor immediately if you experience:

• liver problems--loss of appetite, rash, fever, nausea, vomiting, stomach pain (upper right side), tiredness, itching, clay-colored stools.

Your treatments may be reduced, delayed, or stopped permanently if you have certain side effects.

Common side effects of pexidartinib may include:

• abnormal lab tests;
• tiredness;
• swelling inside or around your eyes;
• changes in hair color;
• rash, itching, hives, skin redness, acne; or
• decreased or altered sense of taste.

This is not a complete list of side effects and others may happen. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Usual Adult Dose for Giant Cell Tumor of Bone:

250 mg orally 2 times a dayTreatment duration: Until disease progression or unacceptable toxicityComments:-Take with a low-fat meal (approximately 11 to 14 grams of total fat).-Taking with a high-fat meal increases the drug's concentrations and may increase the risk of adverse reactions, including hepatotoxicity.Use: For symptomatic tenosynovial giant cell tumor associated with severe morbidity or functional limitations and not amenable to improvement with surgery

Skip the missed dose and take your next dose at the usual time. Do not take two doses at once.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Avoid taking a proton pump inhibitor, such as omeprazole, lansoprazole, pantoprazole, and others. Ask your doctor before taking any medicine to reduce stomach acid and take only the type your doctor recommends.

Grapefruit may interact with pexidartinib and cause side effects. Avoid consuming grapefruit products.

Avoid taking an herbal supplement containing St. John's wort.

Avoid eating foods high in fat (about 55 to 65 grams of total fat), or you may be more likely to have side effects.

Pexidartinib could make you sunburn more easily. Avoid sunlight or tanning beds. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors.

Sometimes it is not safe to use certain medicines together. Some drugs can change the levels of other drugs in your blood, which may increase side effects or reduce how well the medicines work.

Pexidartinib can harm your liver, especially if you are also using certain medicines for infections, birth control, high cholesterol, seizures, pain, or arthritis (including Advil).

Some medicines can make pexidartinib much less effective or increase the risk of side effects when taken at the same time. If you take any of the following medicines, take them separately from your dose of pexidartinib:

• If you take an antacid that contains aluminum, magnesium, or calcium--Take pexidartinib either 2 hours before or 2 hours after taking the antacid; or
• stomach acid medicines (such as cimetidine, famotidine, nizatidine, and others)--take pexidartinib dose 2 hours before or 10 hours after you take the other medicine.

This list is not complete and many other drugs may affect pexidartinib. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.